The present invention relates generally to food packages, and more particularly concerns an antimicrobial absorbent pad for food products, particularly meat and poultry products.
Traditionally perishable food products such as meat, poultry, fish, and vegetables have been displayed and sold in bulk form, thereby allowing the purchaser to select the item or items to be purchased. This practice was particularly true with respect to meat and poultry products which were most commonly sold by a butcher from a display case. More recently such food products are prepackaged for display and sale. Such packaging, especially with respect to meat and poultry, involves the use of a semi-rigid tray, usually plastic, to contain the food product and a plastic overwrap to seal the product within the tray to maintain the freshness of the contents for a finite period.
Meat and poultry as well as other perishable food products naturally contain liquids and juices and occasionally added water which, with time, will drain from the product. When such food products are packaged within a plastic wrapped tray, these liquids may collect within the tray and may subsequently leak during transportation and handling. Market analysis has also revealed that the consumer finds the existence of free liquid in such packages to be unappealing. Consequently, many such packages today employ an absorbent material in the bottom of the tray to absorb the liquids as they are released from the food product. Whether the liquids from the food products remain free or are absorbed in a pad, such liquids provide a medium for bacterial propagation and for transmitting food-borne pathogens which cause disease in humans.
U.S. Pat. No. 4,576,278 to Laiewski discloses a tray which has a false bottom covering an exudate reservoir. The false bottom is made from a perforated liquid-impermeable thermoplastic film such as polyethylene. The reservoir's volume is maintained by integral standoffs which support the false bottom. An absorbent pad containing a bacteriostatic or bactericidal agent may be placed in the reservoir to inhibit or kill bacteria found in the exudate. Listed bacterial agents include broad spectrum antibiotics such as tetracyclines; penicillin; sorbic acid; alkyl-substituted or alkyl aryl-substituted quaternary ammonium compounds; chlorine containing compounds; iodine compounds; phenol and its derivatives; dehydroactic acid; peroxygen compounds; potassium persulfate; peracetic acid and sodium perborate. The bacterial agents may be applied to the absorbent material in any conventional manner. Because the tray has a false bottom and standoffs, there is no need for the absorbent pad in the reservoir to be constructed to insure that the bacterial agent does not contact the food product.
U.S. Pat. No. 4,738,847 to Roth, Creagan and Speigelberg discloses a multi-ply absorbent product, particularly a facial tissue with virucidal properties. The virucidal composition includes citric acid, malic acid, mixtures of citric acid and malic acid, and combinations of these with sodium lauryl sulfate. The tissue is formed with the virucidal composition confined to an inner layer in order to reduce direct contact between the user's skin and the virucidal composition. The tissue is formed of three plies of crepe wadding which typically has low wet strength. While the multi-ply tissue is designed to keep the virucidal agent from the user's skin, that result is achieved in part by the transitory use of the tissue. If the tissue were left in a liquid, the virucidal composition would rapidly migrate to the tissue's surface.
A liquid absorbing and concealing device which includes both a liquid absorbing bag and a flat bottom tray is disclosed in DuPuis, U.S. Pat. No. 3,156,402. The liquid absorbing bag is composed of two superposed sheets of material which are sealed by heat welding or adhesive around their marginal edges. The sheets may be formed from liquid impervious material such as waxed paper, cellophane, polyethylene, or other thermoplastic or thermosetting plastic materials. Each of the sheets contains a series of openings or holes to permit fluid from the food product to enter the bag from either the top or the bottom by means of gravity and capillary action.
A receptacle for moisture-exuding food products is described in U.S. Pat. No. 4,321,997 and U.S. Pat. No. 4,410,578 both to Miller. The receptacle comprises a supporting member such as a tray or bag and an absorbent pad associated therewith. The absorbent pad comprises a mat of liquid-absorbent material such as wood fluff, an upper liquid-impermeable plastic sheet overlying the absorbent mat, and a bottom plastic sheet underlying the absorbent mat. At least one of the sheets is perforated, and a rigid spacer is disposed between the two sheets to maintain their separation under a compressive load such that the ability of the pad to absorb liquids is unimpaired when the pad is subjected to compressive loading from the food product resting thereon. In this construction, it is preferred that only the bottom sheet be perforated such that when a food product is positioned upon the upper sheet of the absorbent pad, any exuded liquids will flow around the pad and enter the mat by capillary action through the perforated openings in the bottom sheet so as to hold the liquids out of contact with the food product to minimize contamination of the product and maintain its appearance and improve its shelf life.
A receptacle and absorbent pad for containing and displaying food products which tend to exude juices or liquids are disclosed in U.S. Pat. Nos. 4,275,81 and 4,382,507, both to Miller. The pad comprises a mat of liquid absorbent material, an upper liquid impermeable sheet overlying the absorbent mat and a perforated bottom sheet underlying the absorbent mat. When a food product is positioned upon the upper sheet of the absorbent pad, the exuded liquids flow around the pad and enter the mat by capillary action through the perforated openings of the bottom sheet and the liquids are held out of contact with the food product by the impermeable upper sheet. In preferred embodiments the absorbent mat is composed of a relatively thick layer of wood fluff and a relatively thin layer of tissue-like paper wadding which may be interconnected by embossing. In addition, various additives may be added to increase liquid absorbency.
The primary function of each of the above-described devices is to absorb the fluids which are exuded from packaged food products. Leaky packages are among the foremost complaints received by food store operators. Their use in such products, therefore, adds to the cost of the overall products. As a result, a major driving force in the development of such products is to provide an absorbent structure which provides ample absorbency while employing cost-efficient components. Furthermore, such designs should yield products with good wet strength, resilience, and fluid retention characteristics. Products such as tissue tend to break apart when wetted. Such materials also readily release their absorbed fluids when placed under a compressive load. This most notably happens when packages are stacked one upon the other. Finally, such absorptive structures can serve as an additional site for the propagation of bacteria and other food contaminants unless properly treated.